Exosome-based antisense locked nucleic acid delivery for inhibition of type II collagen degradation in chondrocyte

A call for standardization for secretome and extracellular vesicles in osteoarthritis: results show disease-modifying potential, but protocols are too heterogeneous-a systematic review

The currently available osteoarthritis (OA) treatments offer symptoms' relief without disease-modifying effects. Increasing evidence supports the role of human mesenchymal stem cells (MSCs) to drive beneficial effects provided by their secretome and extracellular vesicles (EVs), which includes trophic and biologically active factors. Aim of this study was to evaluate the in vitro literature to understand the potential of human secretome and EVs for OA treatment and identify trends, gaps, and potential translational challenges. A systematic review was performed on PubMed, Embase, and Web-of-Science, identifying 58 studies. The effects of secretome and EVs were analysed on osteoarthritic cells regarding anabolic, anti-apoptotic/anti-inflammatory and catabolic/pro-inflammatory/degenerative activity, chondroinduction, and immunomodulation. The results showed that MSC-derived EVs elicit an increase in proliferation and migration, reduction of cell death and inflammation, downregulation of catabolic pathways, regulation of immunomodulation, and promotion of anabolic processes in arthritic cells. However, a high heterogeneity in several technical or more applicative aspects emerged. In conclusion, the use of human secretome and EVs as strategy to address OA processes has overall positive effects and disease-modifying potential. However, it is crucial to reduce protocol variability and strive toward a higher standardization, which will be essential for the translation of this promising OA treatment from the in vitro research setting to the clinical practice.

Exosomes as natural nanocarrier-based drug delivery system: recent insights and future perspectives

Exosomes are nanosized (size ~ 30-150 nm) natural vesicular structures released from cells by physiological processes or pathological circumstances. Exosomes are growing in popularity as a result of their many benefits over conventional nanovehicles, including their ability to escape homing in the liver or metabolic destruction and their lack of undesired accumulation before reaching their intended targets. Various therapeutic molecules, including nucleic acids, have been incorporated into exosomes by different techniques, many of which have shown satisfactory performance in various diseases. Surface-modified exosomes are a potentially effective strategy, and it increases the circulation time and produces the specific drug target vehicle. In this comprehensive review, we describe composition exosomes biogenesis and the role of exosomes in intercellular signaling and cell-cell communications, immune responses, cellular homeostasis, autophagy, and infectious diseases. In addition, we discuss the role of exosomes as diagnostic markers, and their therapeutic and clinical implications. Furthermore, we addressed the challenges and outstanding developments in exosome research and discuss future perspectives. In addition to the current status of exosomes as a therapeutic carrier, the lacuna in the clinical development lifecycles along with the possible strategies to fill the lacuna have been addressed.

Nanodevices for deep cartilage penetration

Osteoarthritis (OA) is a degenerative joint disease and is the main cause of chronic pain and functional disability in adults. Articular cartilage is a hydrated soft tissue that is composed of normally quiescent chondrocytes at a low density, a dense network of collagen fibrils with a pore size of 60-200 nm, and aggrecan proteoglycans with high-density negative charge. Although certain drugs, nucleic acids, and proteins have the potential to slow the progression of OA and restore the joints, these treatments have not been clinically applied owing to the lack of an effective delivery system capable of breaking through the cartilage barrier. Recently, the development of nanotechnology for delivery systems renders new ideas and treatment methods viable in overcoming the limited penetration. In this review, we focus on current research on such applications of nanotechnology, including exosomes, protein-based cationic nanocarriers, cationic liposomes/solid lipid nanoparticles, amino acid-based nanocarriers, polyamide derivatives-based nanocarriers, manganese dioxide, and carbon nanotubes. Exosomes are the smallest known nanoscale extracellular vesicles, and they can quickly deliver nucleic acids or proteins to the required depth. Through electrostatic interactions, nanocarriers with appropriate balance in cationic property and particle size have a strong ability to penetrate cartilage. Although substantial preclinical evidence has been obtained, further optimization is necessary for clinical transformation. STATEMENT OF SIGNIFICANCE: The dense cartilage matrix with high-negative charge was associated with reduced therapeutic effect in osteoarthritis patients with deep pathological changes. However, a systematic review in nanodevices for deep cartilage penetration is still lacking. Current approaches to assure penetration of nanosystems into the depth of cartilage were reviewed, including nanoscale extracellular vesicles from different cell lines and nanocarriers with appropriate balance in cationic property and size particle. Moreover, nanodevices entering clinical trials and further optimization were also discussed, providing important guiding significance to future research.

Functional Extracellular Vesicles for Regenerative Medicine

The unique biological characteristics and promising clinical potential of extracellular vesicles (EVs) have galvanized EV applications for regenerative medicine. Recognized as important mediators of intercellular communication, naturally secreted EVs have the potential, as innate biotherapeutics, to promote tissue regeneration. Although EVs have emerged as novel therapeutic agents, challenges related to the clinical transition have led to further functionalization. In recent years, various engineering approaches such as preconditioning, drug loading, and surface modification have been developed to potentiate the therapeutic outcomes of EVs. Also, limitations of natural EVs have been addressed by the development of artificial EVs that offer advantages in terms of production yield and isolation methodologies. In this review, an updated overview of current techniques is provided for the functionalization of natural EVs and recent advances in artificial EVs, particularly in the scope of regenerative medicine.

Isolation of cabbage exosome-like nanovesicles and investigation of their biological activities in human cells

There are extensive studies on the applications of extracellular vesicles (EVs) produced in cell culture for therapeutic drug development. However, large quantities of EVs are needed for in vivo applications, which requires high production costs and time. Thus, the development of new EV sources is essential to facilitate their use. Accordingly, plant-derived exosome-like nanovesicles are an emerging alternative for culture-derived EVs. Until now, however, few studies have explored their biological functions and uses. Therefore, it is necessary to elucidate biological activities of plant-derived exosome-like nanovesicles and harness vesicles for biomedical applications. Herein, cabbage and red cabbage were used as nanovesicle sources owing to their easy cultivation. First, an efficient method for nanovesicle isolation from cabbage (Cabex) and red cabbage (Rabex) was developed. Furthermore, isolated nanovesicles were characterized, and their biological functions were assessed. Both Cabex and Rabex promoted mammalian cell proliferation and, interestingly, suppressed inflammation in immune cells and apoptosis in human keratinocytes and fibroblasts. Finally, therapeutic drugs were encapsulated in Cabex or Rabex and successfully delivered to human cells, demonstrating the potential of these vesicles as alternative drug delivery vehicles. Overall, the current results provide strong evidence for the wide application of Cabex and Rabex as novel therapeutic biomaterials.

Antisense Oligonucleotide-Mediated Splice Switching: Potential Therapeutic Approach for Cancer Mitigation

Splicing is an essential process wherein precursor messenger RNA (pre-mRNA) is reshaped into mature mRNA. In alternative splicing, exons of any pre-mRNA get rearranged to form mRNA variants and subsequently protein isoforms, which are distinct both by structure and function. On the other hand, aberrant splicing is the cause of many disorders, including cancer. In the past few decades, developments in the understanding of the underlying biological basis for cancer progression and therapeutic resistance have identified many oncogenes as well as carcinogenic splice variants of essential genes. These transcripts are involved in various cellular processes, such as apoptosis, cell signaling and proliferation. Strategies to inhibit these carcinogenic isoforms at the mRNA level are promising. Antisense oligonucleotides (AOs) have been developed to inhibit the production of alternatively spliced carcinogenic isoforms through splice modulation or mRNA degradation. AOs can also be used to induce splice switching, where the expression of an oncogenic protein can be inhibited by the induction of a premature stop codon. In general, AOs are modified chemically to increase their stability and binding affinity. One of the major concerns with AOs is efficient delivery. Strategies for the delivery of AOs are constantly being evolved to facilitate the entry of AOs into cells. In this review, the different chemical modifications employed and delivery strategies applied are discussed. In addition to that various AOs in clinical trials and their efficacy are discussed herein with a focus on six distinct studies that use AO-mediated exon skipping as a therapeutic strategy to combat cancer.

Antioxidative Effects of Carrot-Derived Nanovesicles in Cardiomyoblast and Neuroblastoma Cells

Oxidative stress is implicated in many diseases, including cardiovascular and neurodegenerative diseases. Because an increased level of oxidative stress causes apoptosis, it is necessary to inhibit cellular responses to oxidative stress. In this study, Carex, a nanovesicle from carrot, was isolated and investigated as a novel biomaterial with antioxidative function in cardiomyoblasts and neuroblastoma cells. A high concentration of nanovesicles was purified from carrots, using size-exclusion chromatography in combination with ultrafiltration. The characterization of Carex demonstrated that it had properties similar to those of extracellular vesicles. Carex showed low cytotoxicity in both H9C2 cardiomyoblasts and SH-SY5Y neuroblastoma cells, when a high level of Carex was delivered to the cells. Carex was further investigated for its antioxidative and apoptotic effects, and it significantly inhibited ROS generation and apoptosis in vitro in myocardial infarction and Parkinson’s disease models. Carex inhibited the reduction of antioxidative molecule expression, including Nrf-2, HO-1, and NQO-1, in both models. Considering its antioxidative function and high production yield, Carex is a potential drug candidate for the treatment of myocardial infarction as well as Parkinson’s disease. Thus, the results demonstrated in this study will contribute to an exploration of a novel drug, using nanovesicles from plants, including carrots.

Single-step equipment-free extracellular vesicle concentration using super absorbent polymer beads

Extracellular vesicles (EVs) contain useful biomarkers for disease diagnosis and are promising biomaterials for the delivery of therapeutic molecules in vivo. Accordingly, an efficient concentration method is necessary for large-scale production or high-throughput isolation of EVs from bulk liquid samples, including culture medium and body fluids, to achieve their clinical application. However, current EV concentration methods, including ultrafiltration, are limited with respect to cost, efficiency, and centrifugation time. In this study, we developed the first single-step, equipment-free EV concentration method using super absorbent polymer (SAP) beads. SAP beads absorb small molecules, including water, via nano-sized channels but expel and thereby concentrate EVs. Consequently, the beads drastically enrich EVs by reducing the solution volume in a single step, without affecting EV characteristics. Moreover, the purity of the concentrated EV solution was high due to the absorption of protein impurities by SAP beads. To further demonstrate the versatility of the method, we showed that SAP beads successfully enrich EVs in human urine samples and culture medium, enabling better isolation performance than conventional ultrafiltration. We believe the newly developed approach and insight gained in this study will facilitate the use of EVs as prominent biomaterials for disease diagnosis and therapy.

Engineering approaches for effective therapeutic applications based on extracellular vesicles

The biological significance of extracellular vesicles (EVs) as intercellular communication mediators has been increasingly revealed in a wide range of normal physiological processes and disease pathogenesis. In particular, regenerative and immunomodulatory EVs hold potential as innate biotherapeutics, whereas pathological EVs are considered therapeutic targets for inhibiting their bioactivity. Given their ability to transport functional cargos originating from the source cells to target cells, EVs can also be used as a therapeutic means to deliver drug molecules. This review aims to provide an updated overview of the key engineering approaches for better exploiting EVs in disease intervention. The emphasis is lying on the preconditioning methods for therapeutic EVs, drug loading and targeting technologies for carrier EVs, and activity control strategies for pathological EVs.

ATF4-modified serum exosomes derived from osteoarthritic mice inhibit osteoarthritis by inducing autophagy

Activating transcription factor 4 (ATF4) is critical for chondrocyte proliferation and bone formation. Exosomes are considered as promising gene-delivery vehicles for the treatment of osteoarthritis (OA). This study utilized the serum-derived exosomes from OA mice as the gene-delivery vehicles for ATF4 gene therapy and explored their therapeutic effects on OA. Meniscus injury-induced OA model was established by the excision of anterior part of medial meniscus in the right knee of C57BL/6J mice. Exosomes were isolated from serum samples of sham and OA mice, and were referred to as sham-Exo and OA-Exo, respectively. ATF4-overexpressing OA-Exo (ATF4-OA-Exo) was developed by introducing ATF4 mRNA into OA-Exo via electroporation. Four weeks after surgery, OA mice received intra-articular injections of sham-Exo, OA-Exo, and ATF4-OA-Exo, respectively. The results showed that intra-articular injection of ATF4-OA-Exo alleviated articular cartilage degeneration or damage and inflammatory response of OA mice. Autophagy was weakened in knee joint cartilage of OA mice, which was partially restored by intra-articular injection of ATF4-OA-Exo. Further in vitro assays revealed that ATF4-OA-Exo promoted chondrocyte autophagy and inhibited chondrocyte apoptosis in the TNF-α- or tunicamycin-treated chondrocytes. Together, ATF4-modified serum exosomes derived from OA mice protect cartilage and alleviate OA progression by inducing autophagy.